I'm seeing 3 GB in 7 KB folders at C:\Program Files\Microsoft SQL Server\100\Setup Bootstrap\Update Cache. It's a 70 GB disk, but 33 Gb is used for pagefile, and a bunch in the winsxs folder so things will need some reorganization soon.

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I just found something in KB2015100. The Cause section says in part: "...When repairing the product or when installing service packs, hotfixes or cumulative updates, should these cached files be found to be missing, an error will be logged as mentioned in
the symptoms section."

it also lists some scripts to try to repair. Sounds like if they have to be moved they could be saved and returned temporarily during patching, however I'd worry there wouldn't be enough space to put them there when needed. I might foldermount another volume
as "Update Cache\" on a test box and see how that works before trying in production. If that works, I can always put "Update Cache\" on a SAN and keep pagefile local a little longer.